O Ring Manifold leak

Help needed for leaking manifold

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bavarian_knuckle
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O Ring Manifold leak

#1

Post by bavarian_knuckle » Fri Sep 14, 2018 4:34 pm

... now I am giving up. I desperately need help!

Was trying to solve my manifold leak on my 57FL and after the now 5th trial I am about to give up.

The bike is all stock (I am even pretty sure the engine was never apart). Stock Manifold, stock clamps, all good stuff!
Used the good red seal rings. Manifold nice aligned to the heads once the Linkert is in place ... but cannot get this damn manifold stop leaking. The last trial I even used high temp sealant on top of the rings ... rear is good, front is leaking.

There are no cracks whatsoever at the head nor the manifold. All part are in really good condition.

At this point I couldn't care less about originality ... I just want this beast stop leaking

Any ideas?

thanks
KLaus



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Re: O Ring Manifold leak

#2

Post by Gotnoclass » Fri Sep 14, 2018 4:51 pm

Can you post pics of your clamps, o rings and manifold?

bavarian_knuckle
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Re: O Ring Manifold leak

#3

Post by bavarian_knuckle » Fri Sep 14, 2018 6:52 pm

hope that helps

The rings are standard Viton red rubber rings

Klaus
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Re: O Ring Manifold leak

#4

Post by mik666 » Fri Sep 14, 2018 9:03 pm

https://www.lowbrowcustoms.com/tite-sea ... tster.html

i used these for a while - they did work but i ended up getting anal and making the stock setup with james manifold gaskets and OEM-design style clamps and just bubble tested it every couple of turns while tightening until i found the right spot - was a pain in the ass but i got it after what seemed for ever

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Re: O Ring Manifold leak

#5

Post by ozwick86 » Sat Sep 15, 2018 12:10 am

Please post a pic with the manifold installed with the bubble test so we can see where the leak is coming from.

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Re: O Ring Manifold leak

#6

Post by Buddhahoodvatoloco » Sat Sep 15, 2018 12:42 am

Try and find a pair of these.
If you have another manifold, try that one.
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Re: O Ring Manifold leak

#7

Post by Gotnoclass » Sat Sep 15, 2018 1:38 am

There’s nothing wrong with the original factory setup. As suggested , please post a pic of the leaks you’re detecting. Your band clamp may have formed a bulged groove in the center, therefore not sealing correctly. I was struggling with leaks that ended up coming from a porous casting near the head’s intake port. Also, test your manifold for flatness at the carb mating surface, and same for you carb. You may find that your carburetor is not flat therefore not seated right to the manifold and visa versa. Use new gaskets (James is the best) and make sure you have the correct phenolic spacer that is missing from your picture. Please post closeup pictures of both your manifold and carb mating surfaces.

Ran

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Re: O Ring Manifold leak

#8

Post by socalrider » Sat Sep 15, 2018 3:16 am

The only method that i have found to work EVERYTIME is to clock the heads. Being it appaers from the fotos that your heads are torqued and gaskets have been used , it would be best to remove the heads, install new head gaskets.start by snuging down heads to the point where you can still rotate them. Install manifold with heads snugged.Hook up air supply to manifold and slowly begin tightening clamps alternating beteewn the two ,rotating heads until you no longer hear air leaking .each head will rotate just enough to get the seal. Check with soapy water to make sure you have no leaks. Once you have determined that you have no leaks, begin torquing heads down in a star pattern . During the torqing process keep the air supply hooked up and check for leaks as you torque. Good luck

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Re: O Ring Manifold leak

#9

Post by RUBONE » Sat Sep 15, 2018 3:21 am

Stock clamps are fine. Often the biggest issue is overtightening which distorts the O-rings badly. I hate those clamps Buddahood posted and throw away every set I am in contact with.They tend to pull the o-ring and distort worse than any others except maybe the two piece rigid type.

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Re: O Ring Manifold leak

#10

Post by bavarian_knuckle » Sat Sep 15, 2018 9:33 am

thanks guys,

here's the thing. The bike starts first kick when cold (2 primer kicks before), idles perfectly even at very low revs, accelerates great and also runs great. Only tough to start when really hot but I would think that is because of the hydraulic lifters and the bike has around 60k km on the clock (no signs of an engine repair). Idle needle at 2 turns out, HS needle at a around 1.3 turns and No19 main jet. Both spark plugs nicely tanned.

Can't really complain and the bike doesn't show any sign whatsoever of a manifold leak!

I must admit, I run the bike for almost 15 years now and I also never tested the manifold. Last week, I don't know why, I sprayed carb cleaner on the connection between manifold and head and the bike stalled almost instantly ... front and back same reaction. That's the reason why I started this manifold adventure ...

I am currently building my vacuum test device, so the only tool I am using at the moment is the carb cleaner spray.

Manifold flange and carb flange are both mated and are good. The same for the insulator. Anyways, so far I only sprayed at the manifold-head area and it reacts. Strong improvement to the initial situation, but you still hear the engine reacting a tiny bit.

As said, I will build the vacuum test tool and check again.

Did you guys ever try Rons Rubberband as a solution?

best regards
Klaus

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Re: O Ring Manifold leak

#11

Post by Excalibur » Sat Sep 15, 2018 10:44 am

At this stage it would be prudent to confirm diagnosis with a 10psi bubble test.

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Re: O Ring Manifold leak

#12

Post by ozwick86 » Sat Sep 15, 2018 4:18 pm

Manifold flange and carb flange are both mated and are good. The same for the insulator. Anyways, so far I only sprayed at the manifold-head area and it reacts. Strong improvement to the initial situation, but you still hear the engine reacting a tiny bit.
As Excalibur said, you need to attach the manifold adaptor and apply 10 psi to it and spray the entire area with soapy water for the bubble test. You may have a porosity in the manifold or manifold flange and O-Rings.

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Re: O Ring Manifold leak

#13

Post by Gotnoclass » Sat Sep 15, 2018 8:32 pm

bavarian_knuckle wrote:
Sat Sep 15, 2018 9:33 am

Can't really complain and the bike doesn't show any sign whatsoever of a manifold leak!
I am confused. From your first statement that you are desperately need help and you’re almost giving up to this? What is the real issue? If it’s not broken why are you trying to fix it?

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Re: O Ring Manifold leak

#14

Post by blewcrab » Sat Sep 15, 2018 8:48 pm

if you spray carb cleaner from the left side , the carb can suck it in thru the air cleaner and die . A good test is ….while mc is at idle , close the choke 1 click ….the motor should stumble and try to quit . If it continues to idle with no problem you could have intake leak .

bavarian_knuckle
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Re: O Ring Manifold leak

#15

Post by bavarian_knuckle » Sat Sep 15, 2018 10:25 pm

thanks guys,

The fact that the air cleaner can suck it in is interesting. Anyways, I will pressure test it properly once I have my tool and then I will see.
I will keep you posted

Klaus

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